cmd/gc: do not reuse bool temporaries for composite equality.
Reusing it when multiple comparisons occurred in the same
function call led to bad overwriting.
Fixes #5162.
R=golang-dev, daniel.morsing
CC=golang-dev
https://golang.org/cl/8174047
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 50e05fc..4e42b18 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -2856,11 +2856,19 @@
typecheck(&call, Etop);
walkstmt(&call);
*init = list(*init, call);
-
- if(n->op == OEQ)
- r = tempbool;
- else
- r = nod(ONOT, tempbool, N);
+
+ // tempbool cannot be used directly as multiple comparison
+ // expressions may exist in the same statement. Create another
+ // temporary to hold the value (its address is not taken so it can
+ // be optimized away).
+ r = temp(types[TBOOL]);
+ a = nod(OAS, r, tempbool);
+ typecheck(&a, Etop);
+ walkstmt(&a);
+ *init = list(*init, a);
+
+ if(n->op != OEQ)
+ r = nod(ONOT, r, N);
typecheck(&r, Erv);
walkexpr(&r, init);
*np = r;
diff --git a/test/fixedbugs/issue5162.go b/test/fixedbugs/issue5162.go
new file mode 100644
index 0000000..b14eae7
--- /dev/null
+++ b/test/fixedbugs/issue5162.go
@@ -0,0 +1,88 @@
+// runoutput
+
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// issue 5162: bad array equality when multiple comparisons
+// happen in the same expression.
+
+package main
+
+import (
+ "fmt"
+ "strings"
+)
+
+const template = `
+func CheckEqNNN_TTT() {
+ onesA := [NNN]ttt{ONES}
+ onesB := [NNN]ttt{ONES}
+ twos := [NNN]ttt{TWOS}
+ if onesA != onesB {
+ println("onesA != onesB in CheckEqNNN_TTT")
+ }
+ if onesA == twos {
+ println("onesA == twos in CheckEqNNN_TTT")
+ }
+ if onesB == twos {
+ println("onesB == twos in CheckEqNNN_TTT")
+ }
+ if s := fmt.Sprint(onesA == onesB, onesA != twos, onesB != twos); s != "true true true" {
+ println("fail in CheckEqNNN_TTT:", s)
+ }
+}
+
+func CheckEqNNN_TTTExtraVar() {
+ onesA := [NNN]ttt{ONES}
+ onesB := [NNN]ttt{ONES}
+ twos := [NNN]ttt{TWOS}
+ onesX := onesA
+ if onesA != onesB {
+ println("onesA != onesB in CheckEqNNN_TTTExtraVar")
+ }
+ if onesA == twos {
+ println("onesA == twos in CheckEqNNN_TTTExtraVar")
+ }
+ if onesB == twos {
+ println("onesB == twos in CheckEqNNN_TTTExtraVar")
+ }
+ if s := fmt.Sprint(onesA == onesB, onesA != twos, onesB != twos); s != "true true true" {
+ println("fail in CheckEqNNN_TTTExtraVar:", s)
+ }
+ if s := fmt.Sprint(onesB == onesX); s != "true" {
+ println("extra var fail in CheckEqNNN_TTTExtraVar")
+ }
+}
+`
+
+func main() {
+ fmt.Print("// run\n\n")
+ fmt.Print("// THIS FILE IS AUTO-GENERATED\n\n")
+ fmt.Print("package main\n\n")
+ fmt.Println(`import "fmt"`)
+
+ types := []string{
+ "int", "int8", "int16", "int32", "int64",
+ "uint", "uint8", "uint16", "uint32", "uint64",
+ "float32", "float64"}
+ tocall := make([]string, 0, 32*len(types))
+ for i := 1; i <= 32; i++ {
+ for _, typ := range types {
+ src := template
+ src = strings.Replace(src, "NNN", fmt.Sprint(i), -1)
+ src = strings.Replace(src, "TTT", strings.Title(typ), -1)
+ src = strings.Replace(src, "ttt", typ, -1)
+ src = strings.Replace(src, "ONES", "1"+strings.Repeat(", 1", i-1), -1)
+ src = strings.Replace(src, "TWOS", "2"+strings.Repeat(", 2", i-1), -1)
+ fmt.Print(src)
+ tocall = append(tocall, fmt.Sprintf("CheckEq%d_%s", i, strings.Title(typ)))
+ }
+ }
+ fmt.Println("func main() {")
+ for _, fun := range tocall {
+ fmt.Printf("\t%s()\n", fun)
+ fmt.Printf("\t%sExtraVar()\n", fun)
+ }
+ fmt.Println("}")
+}
